Why is the z-score taken to be 3 for 99.7% of the data

z_score

#1

Hello,

While we take the z-score as 3 for data lying within 99.7% of the normal distribution,the z-score corresponding to 99.7%ile is actually 2.96 and not 3.
So why do we take 3 and not 2.96 as the z-score??


#2

@shuvayan-The absolute value of z represents the distance between the raw score and the population mean in units of the standard deviation.
as z is distance we take integer value for easy calculation
Hope this helps!
Regards,
hinduja1234